Examine source code of account-container-picker

{
  "manifest_version": 2,
  "name": "container-picker",
  "description": "lets you pick account-container from omnibox",
  "version": "0.1.1resigned1",
  "background": {
    "scripts": [
      "dist/index.js"
    ]
  },
  "omnibox": {
    "keyword": "&"
  },
  "permissions": [
    "contextualIdentities",
    "cookies"
  ],
  "browser_specific_settings": {
    "gecko": {
      "id": "{601ccec9-fb6d-4e8e-93b5-dc628cf81077}"
    }
  }
}